1855.] SUTHERLAND — NATAL. 465 



EXPLANATION OF PLATES XL, XIL, XIIL 



Plate XL 



Fig. 1. Ammonites Soutonii : a, front view of whorls ; b, back view reduced to 



one-fourth of natural size ; c, septal suture, half-natural size. 

 Fig. 2. Ammonites Stangeri : «, front view of whorls ; b, back view, reduced to 



one-fourth of natural size ; c, septal suture, natural size. 

 Fig. 3. Ammonites Gardeni : a, front view of inner whorls ; b, back view, 



natural size ; c, septal suture, enlarged 2 diameters. 

 Fig. 4. Ammonites Umbulazi : a, front view of whorls ; b, back view, natural 



size ; e, septal suture, enlarged 3 diameters. 

 Fig. 5. Baculites sulcatus : a, front view ; b, section of one of the chambers ; 



c, back view of another specimen vnth deeper sulcations. 



Plate XIL 



Fig. 1. Hemiaster Forbesii : a, upper surface; b, under surface ; c, portion of 

 upper surface with ambulacra, perforated tubercles, and encircling 

 granules, magnified. 



Fig. 2, Scalaria ornata : a, natural size ; b, portion of surface, magnified. 



Fig. 3. Solarium pulchellum : a, side view, natural size ; 5, upper view of 

 whorls enlarged 5 diameters. 



Fig. 4. Voluta rigida ; natural size. 



Fig. 5. Chemnitzia Sutherlandii ; natural size. 



Fig. 6. Turritella Meadii : a, natural size ; b, enlarged 3 diameters. 



Fig. 7. Turritella Bonei : a, natural size ; b, portion of surface magnified. 



Fig. 8. Natica multistriata : a, natural size ; 6, portion of the surface magnified. 



Plate XIIL 



Fig. 1. Area Umzambaniensis ; natural size. 



Fig. 2. Area Natalensis : a, outer view of single valve ; b, inner view of the 



same ; natural size. 

 Fig. 3. Trigonia elegans : a, front view ; b, hinge view ; natural size. 

 Fig. 4. Cardium denticulatum : a, natural size ; b, enlarged 3 diameters. 

 Fig. 5. Inoceramus expansus : hinge portion of shell, reduced one-third. 



5. Notes on the Geology o/ Natal, South Africa. 

 By Dr. P. C. Sutherland. 



[In Letters* to Sir R. I. Murchison, V.P.G.S.] 



The sea-coast of Natal, to a distance of twenty to thirty miles inland, 

 appears to be composed of beds of sandstone and shale alternating 

 with trap-rock, the former containing thin layers of woody coal and 

 very faint vegetable impressions. These beds of trap and sedimentary 

 matter are not individually of great extent. Six of each sometimes 

 occur in a linear space of a quarter of a mile. 



The best specimens of the coal yet found are only slightly bitu- 

 minous ; and much is of very inferior character. The thickness of 

 the seams varies from a mere film up to about 2^ to 3 feet. "Where 

 the best coal exists, three seams crop out in a space of 20 feet ; the 

 aggregate thickness of which is upwards of 4 feet. From the 

 manner in which they run into each other, thin out, again thicken, 



* Dated D'Urban, March 13, 1854 ; and Natal, Nov. 3, 1854. 



